Curved-wing rotary bit



'9. E. PUIAIAIIII.

CURVED WING ROTARY BIT.

APPLICATION FILED Nv.27, 1920.

LMP/@19, PAIQDIQAAIIg. 2.2, A922."

JM ATTYS vnarran stares storten n; remnant, or Los ANGELES, CALIFORNIA.

enlever-wine ROTARY Brr.

mancia,

Specification of Letters Patent.

Patented Aug. 22, i922@ Application :filed November 27, 1920. Serial No.426,856.

vide a rotary drill bit so arranged that the cuttingsl made by the drillbit will be forced vtoward the axis of the bit where they may be readilywashed away by a stream df water discharged through the shank of a bitin usual manner. This arrangement whereby the cuttings are forced awayfrom the side edges of the bit andtoward its axiswill also prevent saidcuttings obstructing the rotation of the -bit by said cuttings betweenthe bore cut by the bit and the side edges of the latter.

`llt is a further object of the invention to provide a bit of thischaracter having cutting edges arranged upon its side edges for trimmingthe bore cut bythe bit.

llt is a still further object of the invention to provide a bit which isso constructed as to increase the length of the end cutting edge of thebit without increasing the transverse width of' said bit.

rlhe invention will be readily understood from the following descriptionof the accompanying drawings, in which- Figure l is a side elevation ofthe bit constructed in accordance with the invention.

F ig. 2 is a transverse section on the line e-e of rig. i.

Fig. 3 is a detail section on the line 3-3 of Fig. l.

rlhe bit consists of a blade 1 having the usual shank?, projectingaxially beyond its upper edge and provided with the usual threaded pin 3for coupling the bit to a drill rod. lWater is supplied to the oppositesurfaces of the drill bit in the usual manner through conduits lextending through the shank and discharging against the respectivesurfaces of the bit at its upper edge.

rEhe drill bit instead of comprising a plane packing cutting surface intransverse section is formed substantially S-shaped in transversesection as clearly shown in Fig, 2, the respective loops of the Sextending laterally from opposite sides of the axis of the bit. By thisarrangement pockets 5 are provided in the respective surfaces of thedrill bit at opposite sides of the axis of the same and said pocketsterminate at the side edges of the bit in outwardly curved portions 6.These curved portions 6 are formed as cutting edges which extend thelength'of the side edges of the bit.

The end cutting edge of the bit provided at the lower edge of the samepreferably consists of the two usual cutting edges 7 curving downwardlyfrom the axis of the bit to the respective side edges of the same.rlhese end cutting edges are also curved outwardly from the respectivesurfaces of the bitbeneath the pockets 5 as shown at 8 in Fig. 3 inorder to form end formations for said pockets. A

lt will be observed that a bit as thus constructed provides appreciablylonger cutting f edges 7 for a bit of a certain transverse width thanisobtainable with a bit of plane transverseformation. lt will also beobserved that when a bit as thus constructed is in use the pockets 5will cause the cuttings to be moved toward the axis of the bit insteadof outwardly toward the side edges of the same, it being understood ofcourse that the pockets 5 are arranged in the advance surfaces of thebit when the latter is rotated. lt will also be noted that the sideedges for the bit provide means for trimming the bore cut by the bit,the movement of the cuttings toward the axis of the bit keeping theseside cutting edges free from cuttings so that they may properly trim thebore. rlhe movement of the cuttings toward the axis of the bit will alsopermit more ready rotation of the latter and thereby reduce the powernecessary to drive the bit.

`While l have illustrated and described the invention as applied to atwo wing bit it will be understood that the invention is also applicableto a bit having a greater number l,of wings, Vthe wings of the bitirrespective 'of the number of ille saine being curved to llforinpockets 5 and outwardly curved side yforming side cuttingedges, andcutting 'ends ledges 6 in the advance surfaces of the wings 'upon saidwings curving downwardly and i0 in the direction of rotation. outwardlyfrom the aXis of the bit, and ter- Various changes may be made in theconrnin'ating in cutting edges meeting the Side 5 struction as thus setforth without departing cutting edgesl at substantially right angles.from the spirit of the invention. v In testimony whereof I have signedmy What is claimed is: name to this specication.

A rotary loit having radially curved wings l GEORGE E. PUTNAM.

